LibreOffice 6.1.6 asked for an email and password
Why are you posting a second question which looks like to be the same thing like this one I am not able to log into download. I forgot my password.. Please delete one and specify your problem in more detail. Use the Edit function to add information and do not create a new question or even post as an answer.
This sounds a bit like you are using some cloud service to store files on the internet. If that’s the case you need to follow your cloud service providers password recovery procedure. LibreOffice users answering questions on this site won’t be able to help you in any way.